JPH0340634Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention relates to an improvement of a lead cushion type sharp pencil that retracts the lead to prevent the lead from breaking when writing pressure becomes large.

Conventional technology Conventional lead cushion type sharpening pencils are
As shown in FIG.
and the position relative to the cap E is determined, and a structure in which the chuck tightening spring F and the core cushion spring G are supported by this washer C is common.

Also, Publication No. 18227-18227 and Publication No. 18227
As disclosed in Japanese Patent No. 171392, a core cushion spring in which the core cushion spring is made of a cylindrical molded body of synthetic resin and has elasticity in the axial direction has also been proposed.

Problems to be solved by the invention Although the conventional structure shown in FIG. Since it is only fitted into the core case H, it has the disadvantage that it can easily come off and be lost during disassembly, and two parts, the washer C and the core cushion spring G, are essential.

In order to prevent the above-mentioned core cushion spring G from coming off during disassembly, the spring G is attached to a core fixing chuck A,
A structure has been proposed in which it is integrated with the tightening ring B, core case H, etc., but this has the disadvantage of being complicated and increasing costs.

Also, the above-mentioned Utility Model Publication No. 55-18227 and Utility Model Publication No. 18227
The structure disclosed in Japanese Patent No. 58-171392 not only requires a complicated molding die and a molding process for molding a cylindrical molded article made of synthetic resin with elasticity in the axial direction, but also requires a sharp pencil machine. There is a problem in that the internal structure of the system must also be changed.

Therefore, the present invention eliminates the fear of the core cushion spring being detached or lost, eliminates the need for a washer, reduces the number of parts, and lowers costs, and does not impair the functionality of the core cushion spring in the slightest. The purpose of the present invention is to provide a sharpening pencil that requires only a slight change in structure.

Means for Solving the Problems In the present invention, as stated in the claims of the utility model registration, the core cushion spring that is in contact with the tightening ring that is loosely fitted to the core fixing chuck is formed of a coil spring. At the tip of the core cushion spring on the base side, there is a cylindrical body consisting of a straight cylindrical part formed by tightly wound wire rod and a flange part also formed by tightly wound wire rod and extending radially inward. The distal end surface of the cylinder body is brought into contact with the rear end surface of the tightening ring and the rear end surface of the cylinder distal end member that is integrally coupled with the cylinder body, and the core case of the cylinder body is By adopting a structure in which the chuck tightening spring is in contact with the inner surface of the side, the conventional washer is unnecessary, reducing the number of parts, simplifying the assembly process, and preventing the core cushion spring from coming off or being lost during disassembly. This is what I did.

Embodiment and its operation FIG. 1 shows a first embodiment, in which a tightening ring 2 loosely fitted into a core fixing chuck 1 is connected to an inner cylinder 5 of a base 4 screwed onto a shaft cylinder 3 and a core fixing chuck. It is located between 1 and 1.

The above-mentioned core fixing chuck 1 and tightening ring 2 are as follows:
It is integrally connected to a lead case 6 via the chuck 1, and when excessive writing pressure is applied to the lead (not shown) protruding from the base 4, the arrow mark is moved by the elasticity of the lead cushion spring 8, which is a coil spring. It is configured to move backward in the direction to prevent breakage of the core.

The core cushion spring 8 in the illustrated example is fitted onto the coupling body 7, and its tip on the base 4 side has a straight cylindrical portion 9 having the same diameter as the core cushion spring 8, which is tightly wound with a wire.
and a flange portion 10 tightly wound radially inward from the tip thereof into a flange shape.
The distal end surface of the cylinder 11 is positioned in contact with the rear end surface of the inner cylinder 5 of the base 4, and the distal end surface is in contact with the rear end surface 12 of the tightening ring 2, so that the shaft cylinder 3 and the base are connected. The position of the tightening ring 2 with respect to 4 is determined.

Note that the rear end 13 of the core cushion spring 8 is connected to the shaft cylinder 3.
It is locked to the step part 14 of.

As is clear from the above structure, the cylindrical body 11 integral with the core cushion spring 8 is fitted onto the core fixing chuck 1.

A chuck tightening spring 17 is provided between the inner surface 15 of the cylindrical body 11 and the distal end surface 16 of the core case 6.
is interposed and externally fitted onto the core fixing chuck 1.

FIG. 2 shows a second embodiment, in which the tightening ring 19 of the core fixing chuck 18 is slightly shorter than that shown in FIG. The structure is the same as that of the first embodiment shown in FIG. 1, except for the difference.

That is, as shown in FIG. 2, the tip of the core cushion spring 20, which is a coil spring, has a flange portion 22 that is tightly wound with a wire and projects radially inward in a flange shape, and a base 23 from the inner peripheral edge of the flange portion 22. The cylindrical body 21 is constituted by a straight cylindrical part 24 that extends in the same direction and is tightly wound. When the distal end surface 25 of the flange part 22 comes into contact with the rear end surface 27 of the inner cylinder 26 of the base 23, the straight cylindrical part 24 The position of the front end surface 28 of the tightening ring 19 is determined, and the front end surface 28 is brought into contact with the rear end surface 29 of the tightening ring 19, thereby determining the position of the tightening ring 19.

Inner surface 30 of cylindrical body 21, that is, flange portion 22
A chuck tightening spring 33 is interposed between the rear end surface and the front end surface 32 of the lead case 31.

FIG. 3 shows a third embodiment, in which the base 34
An inner cylinder 36 is formed at the threaded portion of the shaft cylinder 35 that is screwed together with the shaft cylinder 35, and the inner surface of the shaft cylinder 35 is formed into a straight cylinder surface having a concave groove 37, and the inner cylinder 36 of the shaft cylinder 35 and A tightening ring 39 is interposed between the core fixing chuck 38 and the core fixing chuck 38.

The rear end surface 40 of the inner tube 36 serves as a positioning portion for a cylinder 42 of a core cushion spring 41, which will be described later, and also serves as a locking portion for the core cushion spring 41 in a recessed groove 37 on the inner surface of the shaft tube 35.

The core cushion spring 41, which is a coil spring, has a second
Similar to the core cushion spring 20 shown in the figure, the flange portion 43 has a flange portion 43 whose tip is tightly wound with a wire rod and protrudes radially inward in the form of a flange.
A cylindrical body 42 is constituted by a straight cylindrical part 44 which is also closely wound and extends from the inner peripheral edge of the flange 3 in the direction of the base 34, and the distal end surface 45 of the flange part 43 abuts the rear end surface 40 of the inner cylinder 36. The position of the tightening ring 39 relative to the base 34, the shaft tube 35, and the core fixing chuck 38 is determined by the distal end surface 46 of the straight cylindrical portion 44 coming into contact with the rear end surface 47 of the tightening ring 39.

The rear end of the core cushion spring 41 is an enlarged diameter portion 48, and this enlarged diameter portion 48 is formed into a concave groove 3 on the inner surface of the shaft cylinder 35.
7, and the position of the core cushion spring 41 with respect to the shaft cylinder 35 is regulated.

Incidentally, the arrangement position of the chuck tightening spring 49 is the same as in the second embodiment shown in FIG.

Further, the portion of the cylindrical body around which the coil spring is tightly wound may be solidified with solder, adhesive, or the like.

As shown in each of the above-mentioned embodiments, a cylindrical body that positions the tightening ring with respect to the base and the shaft cylinder and also serves as a seat for the core cushion spring and the chuck tightening spring is formed integrally with the core cushion spring, and the cylinder body is formed integrally with the core cushion spring to fix the core. Since it is assembled into an assembly consisting of the chuck, tightening ring, and core case, there is no risk of the core cushion spring coming off or being lost even if it is disassembled.

The cylindrical body can be manufactured at the same time as the core cushion spring is manufactured, and there is no need to manufacture the washer as a separate process as in the past.
In the assembling process, the cylindrical body instead of the washer can also be assembled by simply assembling the core cushion spring, which not only reduces the number of parts but also shortens the manufacturing and assembling processes.

Effects of the invention The present invention has the structure and operation described above, and eliminates the fear of the core cushion spring coming off or being lost during disassembly.It also eliminates the need for conventional washers, which reduces the number of parts and reduces the number of parts in the manufacturing process. This has various effects such as simplifying the assembly process and reducing costs.

Moreover, it has the advantage of not impairing its function as a core cushion type sharp pencil or complicating its structure.

In addition, the cylindrical body on the base side of the core cushion spring, which is a coil spring, has a straight cylindrical part formed by tight winding and a flange part projecting inward in the radial direction, so that the cylindrical body of the core cushion spring, which is a coil spring, has a straight cylindrical part formed by close winding and a flange part that protrudes radially inward. Since it can easily come into contact with the member, the structure of the core cushion type mechanical pencil does not become complicated, only slight changes in the structure are required, and the function is not impaired in the slightest.

[Brief explanation of the drawing]

FIG. 1 is a half-cut enlarged cross-sectional view of the first embodiment;
The figure is an enlarged half-cut sectional view of the second embodiment, FIG. 3 is an enlarged half-cut sectional view of the third embodiment, and FIG. 4 is an enlarged half-cut sectional view of the conventional product. 1: Core fixing chuck, 2: Tightening ring, 4: Base, 8: Core cushion spring, 9: Straight cylinder part, 10:
Flange part, 11: Cylindrical body, 12: Rear end surface, 15:
Inside, 17: Chuck tightening spring.

Claims (1)

[Scope of utility model registration request] The core cushion spring that is in contact with the tightening ring that is loosely fitted to the core fixing chuck is formed of a coil spring, and the tip of the core cushion spring on the base side has a straight cylindrical portion formed by tightly wound wire material, A cylindrical body is also formed by tightly wound wire and has a flange portion that extends radially inward, and the distal end surface of the cylindrical body is integral with the rear end surface of the tightening ring and the shaft cylinder. A lead cushion type sharp pencil in which a chuck tightening spring is brought into contact with the rear end surface of a shaft cylinder tip end member connected to the barrel, and a chuck tightening spring is brought into contact with the inner surface of the cylinder body on the lead case side.